Domhnall II, Earl of Mar
It appears likely that he fought on the side of Edward II of England at the Battle of Boroughbridge in March 1322, as it is recorded that afterwards the Earl of Mar took Bartholomew de Badlesmere, who was one of Edward's captured opponents, to Canterbury.
In 1332 the regent of Scotland, Thomas Randolph, 1st Earl of Moray, died. On 2 August Domhnall was elected as the new regent at a meeting of the Scottish nobles at Perth. Following the invasion of Edward Balliol, with the support of Edward III of England, Mar led the Scots loyalists to confront them. He was defeated and killed at the Battle of Dupplin Moor, only nine days after his election as regent.
Through his marriage to Isabella Stewart, daughter of Sir Alexander Stewart of Bonkyll and Jean Fitz James, they had a son, Thomas of Mar, and a single daughter, Margaret of Mar, who succeeded her brother and became, in her turn, Countess of Mar.
| Mormaer of Mar
Thomas Randolph, 1st Earl of Moray
| Regent of Scotland
2–11 August 1332
Sir Andrew Murray
- Watson, F (2004). "Donald, Eighth Earl of Mar (1293–1332)". Oxford Dictionary of National Biography (online ed.). Oxford University Press. doi:10.1093/ref:odnb/18021. Retrieved 12 December 2015.(Subscription or UK public library membership required.)
- Glover, John (1865). Le Livere de Reis de Britannie E Le Livere de Reis de Engletere (edited). London. pp. 342–3.
- "Mar, Donald (1293?-1332)". Dictionary of National Biography. 36: 117. 1885–1990. Retrieved 27 January 2019.
- "Mar, Donald (1293?-1332)". Retrieved 27 January 2019.